FIG. 1.
Schematic diagram of plasmid used to generate recombinant MHV76-K1 virus. The expression cassette consists of the CMV-IE promoter and the EGFP-Hygr gene from pEGFPHyg (Clontech), followed by the IRES element from EMCV. Cloned immediately downstream from the IRES is the KSHV K1 ORF followed by the SV40 poly(A) signal (pA). These elements were cloned into a BamHI site next to the MHV-76 genomic DNA (nucleotides 9539 to 12569 of MHV-68) in pBluescript (Stratagene). The MHV76-GFP virus was generated by using an identical plasmid lacking the KSHV K1 gene. The positions of the probes used for Southern hybridization (BamHI-XmaI and SacII-XmaI) and the restriction sites for NheI and MfeI are indicated.